Last week, I talked about histamine intolerance—a condition that’s been gaining traction lately in the alternative medicine and holistic nutrition communities. The idea behind it is that some people are especially sensitive to histamines found in certain foods. Although histamine intolerance is not technically an allergy, a low-histamine diet might relieve pesky and otherwise unexplained allergy-like symptoms -- such as itching, wheezing, sinusitius, nausea, and skin rashes -- in those with a heightened sensitivity.

The challenge, as I explained last week, is that there’s a lot of conflicting information about the histamine content of foods. This week, I’m going to try to clarify, and hopefully simplify, which foods you might want to avoid if you’re inclined to test the theory on yourself.>

Where do Histamines Come From?

At first glance, lists of high-histamine foods that you'll come across on the Internet can seem somewhat random: sauerkraut, pepperoni, and strawberries? You’ll also notice a lot of foods that we generally think of as healthy, such as fish and yogurt, listed there. I think these lists will make more sense to you once you understand where histamines come from.

Most of the histamine content in food is the result of bacterial activity. Although you may not like to think about it, bacteria are almost always present in raw meat and fish. In fact, that’s what gives raw meat such a short shelf-life—the bacteria eventually cause the meat to spoil.

Refrigeration slows down bacterial activity (and delays spoilage), but the longer meat is stored before (or even after) it’s cooked, the higher the histamine content will be. Unfortunately, although cooking kills bacteria, it does not remove histamines.

Fish and shellfish tend to be even higher in histamines than red meat or poultry, due to the particular strains of bacteria they tend to host. And again, the less fresh the fish, the higher the histamine content.

Histamines in Cultured and Fermented Foods

However, the bacterial activity that turns cabbage into sauerkraut, milk into yogurt, and grapes into wine or vinegar can also produce histamines. But the histamine content of fermented foods will vary dramatically, depending on exactly how and where it was prepared. With that in mind, let’s take a look at which foods are likely to be the highest in histamines.